In conventional skating shoes described in the U.S. Pat. No. 6,450,509, a roller is mounted on a rear lower part of the shoe. In walking mode, the shoe is horizontally arranged so that a friction member at a front lower part of the shoe and the roller endure the user's weight together. In skating mode, the shoe is backwardly slanted so that only the roller endures the user's weight.
The Korea Patent No. 10-0518113 (entitled “wheel-mounted type shoes”) is to solve the problem of rolling in walking mode, which is described in the U.S. Pat. No. 6,450,509. Referring to FIG. 12A, a roller is mounted on an upper part than a bottom part of an outsole of the shoe so that the roller does not contact to the ground in walking mode. In this structure, the roller 2 should be mounted on an outer edge of the outsole 1 of the shoe where the user's ankle is bent relatively more than an inner edge.
In other words, in walking mode, all of the outer and inner edges of the outsole and a part between the two edges are contacted to the ground in walking pose with the shoes being horizontally arranged. In skating mode, the shoe is slanted outwardly so that the roller is contacted to the ground in the pose of “O” character type legs.
On the other hand, there are skating methods as follows:
A pushing method is a method that generates self driving force by direct angular movement to the ground while the roller moves in horizontal direction when a user stretches his legs in horizontal direction at the time of acceleration. Particularly, in the inline skate, pushing is skating itself.
A gliding method is a skating method that a user proceeds forward by gravity like as down-hill of a snow board or inertia. However, this method is not constant and impractical because it cannot generate self driving force in case of flat or uphill road.
The pushing conditions are as follows:
Straight nature: a roller should be arranged so that a sufficient distance between the roller axis is obtained in a column (aligning shoes in front and rear direction), thereby allowing a driving course to be fixed so that driving force is not dissipated while pushing.
Inward slant (slanting a shoe inwardly): the outer edge of the lower part of the shoe is raised upward and the inner edge is slanted so as to contact to the ground while right and left legs of the user reciprocate in horizontal direction. In this time, a structure, where the roller can well contact to the ground, is required.
Height: stable one foot standing should be possible with a leg for enduring the user's weight when the user folds his leg used for pushing after pushing so that the lower part of the shoe does not contact to the ground by unevenness (concave and convex) of the ground at the time of skating or pushing. In this time, because it may be very dangerous if the user drops down when the user loses his/her balance and the lower part of the shoe is contacted to the ground, a structure that ensures sufficient height is required.
Roller specification: large diameter is required so as to transfer pushing force to the ground effectively without stumbling of the roller by the unevenness. Wide width is required so that the user can easily keep his balance at the time of one foot standing.
Conventional skating shoes are analyzed below based on the conditions for enabling the pushing method.
In U.S. Pat. No. 6,450,509, a roller is provided only on a rear part of a shoe and accordingly, it is difficult to fix direction and thus, the shoe does not have the straight nature. The user's body should be bent forwardly so as to stand to acceleration, but on the contrary, the weight is loaded on the rear part and one foot standing is particularly difficult.
In Korea Patent No. 10-0518113, if the user tries pushing, the inner edge of the outsole contacts to the ground and the roller at the outer edge is raised upwardly so that the pushing action itself is impossible.
Further, because the roller is provided on the upper part of the outsole, it is difficult to prevent the outsole for one foot standing from contacting to the ground. Particularly, as shown in FIG. 12B, the outsole near the roller 2 probably stumbles on the unevenness 6 so that the user drops down. In addition, it is difficult for the user to skate or push normally because the above structure should use a roller of relatively small diameter and narrow width. Accordingly, the user can do the gliding restrictively only when the road is sloppy, and it may become more dangerous regardless of solution of the rolling phenomenon.